Sheet feeding mechanism



July 1, 1958 R. K. NORTON SHEET FEEDING MECHANISM 2 Sheet s-Sheet 1Filed April 7, 1954 INVENTOR. ROBERT K AORTO/V I. MW

y 1, 1958 R. K. NORTON SHEET FEEDING MECHANISM 2 Sheets-Sheet 2 FiledApri l 7, 1954 INVENTOR. RGBERT K AURTO/V BY /3 I ATTOENEYS 2,8415%"1Patented July 1, 1%58 easiest sneer Rename linens Robert K. Norton,'fwinshurg, Ohio, assignor to Harrisintertype Corporation, a corporationof This invention relates to improvements in sheet feeding mechanism,particularly mechanism for feeding sheets one at a time from the top ofa pile of sheets and over an endless conveyor to a printing press or thelike.

One of the objects of the invention is the rrovision of a feeder of thecharacter stated in which the forwarding device disposed above the topof the pile of sheets op crates at speeds varying from minimum tomaximum, back again to minimum during each cycle, and in which thesheets are taken at the point of minimum speed.

Another object is the provision of a feeder of the character stated inwhich the sheets are transferred by the forwarding device to an endlessconveyor which transports them to front guides and in which the endlessconveyor partakes of changes in speed varying synchronously with thechanges in speed of said sheet forwarder.

Still another object is the provision of a feeder of the characterstated in which the forwarding device is a rotating vacuum wheel, and inwhich the distance between the front guides and the forward edge of thetop sheet of the pile may be equal to the circumference of the saidwheel or a multiple thereof, whereby the taking of one sheet by thesheet forwarder and the registering of a preceding sheet against thefront guides may occur simultaneously.

A further object is the provision of means for adjusting the angularposition of the vacuum wheel on its shaft, whereby the simultaneousaction of the forwarding means and the registering of sheets may bemaintained regardless of variations in the character of the stock beingfed and regardless of wear in the mechanism.

Other objects and features of novelty will appear as I proceed with thedescription of that embodiment of the invention which, for the purposesof the present application, I have illustrated in the accompanyingdrawings, in which:

Fig. 1 is a diagrammatic side elevational view of a sheet feederembodying the invention;

Fig. 2 is a fragmental sectional view taken substantially on the line2-2 of Fig. 1 showing common means for driving synchronously at varyingspeeds the sheet forwarding means and the tape conveyor;

Fig. 3 is a fragmental top plan view taken substantially on the line 3-3of Fig. 1;

Fig. 4 is a detail view on a larger scale partly in section on the linei-d of Fig, 2; and

Fig. 5 is a fragmental perspective view showing diagrammatically frontguides at the forward end of a feed board and sheet grippers on animpression cylinder, at approximately the time when a sheet is beingtaken by the cylinder grippers.

Referring to Fig. 1, i represents a pile of sheets supported upon a pileboard 11 which is adapted to be raised an increment at a time by liftingchains 12 in a manner well-known in the art. A flat plate 13 issupported a slight distance above the top of the pile by brackets 14carried upon transverse bars 15 supported in the frame of the machine.Plate 13 is slotted to receive the lower periphery of a vacuum wheel 16which is of more or less conventional form. The wheel is mounted upon atransverse shaft 17 with a bushing 18 interposed in order that the wheelmay have a limited angular adjustment upon the shaft. This adjustment isaccomplished by mounting a pin 2% in a hole in the wheel, the pin alsoextending through a slot 21 in an arm 22 mounted upon the shaft and heldagainst rotation thereupon by a key 23 which is adapted to slide in akeyway in the shaft. The pin 29 has an integral collar 24 adapted toengage one surface of the arm 22. in the opposite surface a washer 25 isinset and a nut 21 is threaded on the pin so that when the nut is drawnup tight the arm is firmly gripped between the washer and the collar 2d.As will be obvious the vacuum wheel may be angularly adjusted byloosening the nut 26, turning th wheel to the desired position andretightening the nut. if it becomes desirable to move the wheellengthwise of the shaft that may be done by loosening a setscrew 27 whenthe wheel with its arm 22 may he slid along the shaft to the desiredpoint and the setscrew 27 then again tightened. Washer 25 has a pointedouter end which cooperates with a scale 29 on the rim of the wheel 16,which serves as an indicator to show that the wheel has been adjustedfrom its normal position angularly in either direction. A sp 3t)interposed between the arm 22 and the wheel 16 urg s the wheel against aleather washer 28 communicating x a vacuum line. The washer 23 acts as aseal against the adjacent side of the wheel 15. Wear in the washer willbe compensated for by the spring 39.

In the wheel to there are a series lateral holes 31 which communicatewith radial openings 32. As the wheel rotates the holes 31 are adaptedto register one after another with a port 3 in the washer 28 and fitting34. The fitting 34 is mounted upon a bracket 35 carried by one of thebars and receives one end of a. flexible conductor which extends to asource of vacuum. When the wheel 15 reaches the position of rotationillustrated in Fig. l, the first hole 31 re, with the port 33 andsuction becomes effective t and grip the uppermost sheet the pile. Asthe vxneel rotates clockwise, as viewed in Fig. l, vacuum is applied tosubsequent holes 3?. to grip the sheet. The grip of the wheel on thesheet continues and moves it forward until a lateral groove 37 comesinto register with the port 33, whereupon the suction is broken. By thattime however the forward edge of the sheet has reached the bight betweengravity rollers 38 and roller 40 over which run the tapes 3? of anendless conveyor. Gravity rollers 33 are journaled in the rear ends ofarms d]; which are oscillatably mounted on a transverse rod fixed in theframe. The upper runs of tapes travel over a feed board 43 and thencearound an idler roller 3 2.

Forwa l' beyond the tapes there is a feed board extension a the forwardend of which there are front guides with sheet grippers 48 that takeeach sheet as it en"= the press, the remaining portions of which are notI lustrated.

The drive for the sheet forwarding wheel is; and endless conveyor issubstantially as follows.

At one end of impression cylinder 47 there is a. g 5% the pitch circleof which has the same diameter as the circumference of the cylinder. Atrain of gears, such as 51 and 52, carry the drive from gear 59 to agear 53 which is journaled upon a stub shaft 54 that is fixed in a framebracket 55. in a laterally projecting part of gear 53 there is a radialslot 56. A gear 57 which is preferably of the same diameter as gear 53,and consequently of the same. diameter as gear 56, with its axisparallel to. but slightly offset from the axis of gear 53,

.is rotatably mounted on a stub shaft 58 that is fixed in one of theframe members 59 of the machine.

Gear 57 is driven at varying speeds by means of a roller 66 mounted on apin that is fixed in the gear, the roller running in slot 56 of gear 53.This form of drive results in a constantly varying motion of gear 57from minimum speed up to maximum speed and back again to minimum speedduring each revolution of constant speed gear 53; At the position shownin the drawings the rotation of gear 57 is at its minimum speed point.Since at this point the roller 60 is spaced materially from the axis ofshaft 54, the minimum speed of shaft 58 is obviously greater than zero.V

A sprocket wheel 61 is fastened to one side of gear 5 7, and over'thissprocket wheel and a sprocket wheel upon which the roller 40 is mounted,the pitch circle of.

gear 64 being the same as the circumference of the roller. Consequentlythe circumferential speed of'the pitch circle of gear 57 and the surfacespeed of roller 40 are the same, and since the circumference of thevacuum wheel 16 turns at the same speed as the'pitch circle of gear 57,the surface speed of the conveyor and of the vacuum wheel are the same.The wheel 16 and tapes 39 are driven at a speed greater than press speedfor a short time in each cycle to make up for the period during whichtheir speed is reduced.

A plurality'of nozzles 66 disposed beneath wheel 16 transmit a blast ofair against the underside of plate 13. A suction is thereforecreated'between the plateand the top'of the pile which tends to lift thetop sheet against the plate. The nozzles 66 then assist in flufling theupermost sheets of the pile. The wheel grips the sheet at approximatelyits minimum speed, which is materially lower than maximum speed. Thesuction grip of the wheel upon the sheet is therefore readily effected.As the wheel accelerates the sheet is drawn off under the plate 13, theair blastserving to float the'sheet, or at least the middle portionthereof, and thus facilitating its movement. The sheet is to be advancedinto the grip eifectedby roller 40 and rollers 38 while traveling at thesame speed as roller 40 and is to be taken onto the endlessconveyortapes 39 and fed forward toward the press. Shortly after the forwardedge of the sheet begins its travel on the conveyor the groove 37 in thevacuum wheel exhausts the suction to the atmosphere and the sheet isthen under the control of the conveyor exclusively. Gravity wheels 68and 69 disposed above the tapes 39 insure'good traction of the tapesupon the sheet. As shown,'the distance between the front guides 46 andthe forward edge of the top sheetof the pile is the same as thecircumference of wheel 16. Consequently at the time the wheel takesinvention sheet S should reach the registering point too early in thecycle, it might pass the front guides before they would move .intoposition to stop the sheet. On

the contrary if the sheet should reach the front registering.

'the front edge of one sheet S the preceding sheet S point too late,sheet detecting mechanism operable when.

nosheet is present would actuate conventional throwoff mechanism to tripthe cylinders of the press to impression off position. The presentinvention provides an adjustment of a very simple character whichinsures the arrival of the sheet S at the registering point at preciselythe right moment. 7 The driving mechanism is not in any. way affected orchanged, and the synchronized relationship between the vacuum wheel andthe conveyor is not disturbed whenever an adjustment is made tore-timethe advance of sheets to the front stops. 7

Although in the present disclosure the distance between the front guidesand the forward edge of the top sheet of the pile is the same as thecircumference of the vacuum wheel, it should be understood that thisdistance may be a multiple of such circumference;

Having thus described my invention, I claim: m

1. In a sheet feeder, a rotary vacuum wheel sheet forwarding device, anendless conveyor device adapted to receive sheets from said forwardingdevice, front guides against which the sheets are registered by saidconveyor,

means for driving said devices synchronously at speeds varying from aminimum speed above zero to maximum and back to minimum duringv eachcycle, the taking of a sheet by said forwarding device and theregistration of a preceding sheet againstsaid front guides occurring atabout said minimum speed. i e

2. In a sheet feeder, a rotary vacuum wheel sheet forwarding device, anendless conveyor device adapted to rceive sheets from said forwardingdevice, front guides against which the sheets are registered by saidconveyor device, ashaft by which the forwarding device is op erated, ashaft by which the conveyor device is driven, means for driving saidshafts synchronously at varying speeds during each cycle, and means foradjusting said sheet forwarding device relatively'to its shaft.

3. A sheet feeder substantially as defined in 'claim 2,

wherein the means for driving said shafts comprises a common rotatingelement the speed of which varies from a minimum speed above zero tomaximum and back again to minimum during each cycle. i

4. A sheet feeder substantially as defined claiin l,

wherein the means for driving said devices comprises a common rotatingelement the speed of which varies from minimum to maximum and back againto duting each cycle, and means for making effective suction in" saidvacuum wheel for a short interval while the wheel' is rotating at aboutminimum speed. v

5; A sheet feeder substantially as defined in. claim 2, wherein themeans for driving said shafts comprises a common rotating element thespeed of which varies from a minimum to maximum and back again to am;ing each cyclefmeans for making effective suction fin said vacuum wheelfor a short interval while said wh eelf.

is rotated at about'minimum speed, and wherein said adjusting meanscomprises means for-lockingsaidvac-Q; uum wheel in various angularpositions upon itsshaft, whereby any' slippage of sheets on said wh e'elmay be" compensated for by said adjusting means and the simultaneoustaking of a sheet by the wheel and registering of: a preceding sheetagainst the front guides may bem aintained regardless of the characterof stock being fedl'l 6. In mechanism of the character described, aprinting cylinder, an endless conveyor adapted to'carry sheets forwardto said cylinder, front guides at the point'of transfer from saidconveyor to said cylinder, a sheet forwarder comprising a vacuum wheeldisposed above a pile of sheets and adapted to take sheets one at a timefrom said pile and transfer them to said conveyor, the distance betweenthe said front guides and theforward edge of the top sheet of the pilebeing equal to or a multiple of the circumference of said wheel, andmeans for adjusting said vacuum wheel .angularly upon its shaft tocompensate" for differences in the character of the stock being fed. ,7V

7. In mechanism of the character -described,a'vacuun'1 wheel sheetforwarder disposed above a pile of sheets, a feed board disposed forwardof said vacuum' wheel, an

endless conveyor running over said feed board, pull-out rolls disposedat the rear end of. said endless'conveyor,

a shaft driven at constant speed, a rotating element turn ing aboutan'axis parallel to said driven shaft, said elementoperatively connectedto said driven shaft to turn at a variable speed from minimum to maximumand back again to minimum during each cycle, said element having onedriving connection with said pull-out rolls and another drivingconnection with said vacuum wheel to impart the same surface speed tosaid vacuum wheel and said pull-out rolls, and means for adjusting saidvacuum wheel angularly.

8. A sheet feeder substantially as defined in claim 1, including meansfor making efiective suction in said vacuum wheel for a short intervalwhile said wheel is rotating at about minimum speed, and means foradvancing or retarding the application of said vacuum to compensate forrelative slippage between said sheets and said wheel.

9. A sheet feeder substantially as defined in claim 8,

wherein said means for advancing or retarding the applicatlon of vacuumcomprises means for adjusting said vacuum wheel angularly about itsshaft.

References Cited in the file of this patent UNITED STATES PATENTS2,157,849 Danielsson Q. May 9, 1939 2,159,147 Gumbel May 23, 19392,220,073 Belcher et a1. Nov. 5, 1940 2,227,370 Seybold Dec. 31, 19402,231,339 Krueger Feb. 11, 1941 2,313,100 Stevens Mar. 9, 1943

